====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.6.4878/26133 is trying to acquire lock: ffff8880742cbeb8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x323/0x1b70 fs/ext4/inode.c:604 but task is already holding lock: ffff888023e34208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x12b/0x190 fs/quota/quota_v2.c:357 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&s->s_dquot.dqio_sem){++++}-{3:3}: down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520 v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:335 dquot_acquire+0x152/0x520 fs/quota/dquot.c:463 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6831 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x333/0xcd0 fs/quota/dquot.c:1517 ext4_process_orphan+0x54/0x300 fs/ext4/orphan.c:327 ext4_orphan_cleanup+0xbeb/0x1420 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5556 [inline] ext4_fill_super+0x7829/0x7dc0 fs/ext4/super.c:5687 get_tree_bdev+0x3f1/0x610 fs/super.c:1366 vfs_get_tree+0x88/0x270 fs/super.c:1573 do_new_mount+0x24a/0xa40 fs/namespace.c:3078 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&dquot->dq_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xaf0 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6811 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412 __dquot_alloc_space+0x5fc/0xe60 fs/quota/dquot.c:1752 dquot_alloc_space_nodirty include/linux/quotaops.h:300 [inline] dquot_alloc_space include/linux/quotaops.h:313 [inline] dquot_alloc_block include/linux/quotaops.h:337 [inline] ext4_mb_new_blocks+0xf8d/0x4760 fs/ext4/mballoc.c:5738 ext4_ext_map_blocks+0x195b/0x6810 fs/ext4/extents.c:4340 ext4_map_blocks+0x9de/0x1b70 fs/ext4/inode.c:679 _ext4_get_block+0x1e7/0x540 fs/ext4/inode.c:822 ext4_get_block_unwritten+0x2a/0x100 fs/ext4/inode.c:855 __block_write_begin_int+0x55d/0x1a80 fs/buffer.c:1991 ext4_convert_inline_data_to_extent fs/ext4/ext4_jbd2.h:-1 [inline] ext4_try_to_write_inline_data+0x81b/0x1150 fs/ext4/inline.c:761 ext4_write_begin+0x28f/0xf80 fs/ext4/inode.c:1204 ext4_da_write_begin+0x30a/0x960 fs/ext4/inode.c:3000 generic_perform_write+0x2fa/0x5c0 mm/filemap.c:3862 ext4_buffered_write_iter+0x11a/0x390 fs/ext4/file.c:285 ext4_file_write_iter+0x1cf/0x1710 fs/ext4/file.c:-1 do_iter_readv_writev fs/read_write.c:-1 [inline] do_iter_write+0x642/0xb10 fs/read_write.c:861 iter_file_splice_write+0x699/0xcc0 fs/splice.c:685 do_splice_from fs/splice.c:763 [inline] direct_splice_actor+0xe1/0x130 fs/splice.c:950 splice_direct_to_actor+0x48b/0xb90 fs/splice.c:896 do_splice_direct+0x1ce/0x2f0 fs/splice.c:1002 do_sendfile+0x5f3/0xea0 fs/read_write.c:1255 __do_sys_sendfile64 fs/read_write.c:1323 [inline] __se_sys_sendfile64+0x141/0x1a0 fs/read_write.c:1309 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&ei->i_data_sem/2){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2d07/0x7d10 kernel/locking/lockdep.c:5049 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662 down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x323/0x1b70 fs/ext4/inode.c:604 ext4_getblk+0x1cc/0x6f0 fs/ext4/inode.c:890 ext4_bread+0x26/0x170 fs/ext4/inode.c:946 ext4_quota_write+0x236/0x580 fs/ext4/super.c:7222 write_blk fs/quota/quota_tree.c:70 [inline] get_free_dqblk+0x312/0x660 fs/quota/quota_tree.c:136 do_insert_tree+0x22b/0x1040 fs/quota/quota_tree.c:347 do_insert_tree+0x9eb/0x1040 fs/quota/quota_tree.c:402 dq_insert_tree fs/quota/quota_tree.c:432 [inline] qtree_write_dquot+0x49d/0x5d0 fs/quota/quota_tree.c:451 v2_write_dquot+0x108/0x190 fs/quota/quota_v2.c:361 dquot_acquire+0x2d5/0x520 fs/quota/dquot.c:472 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6831 dqget+0x778/0xeb0 fs/quota/dquot.c:988 dquot_transfer+0x37c/0x7e0 fs/quota/dquot.c:2150 ext4_setattr+0x93d/0x19f0 fs/ext4/inode.c:5520 notify_change+0xc74/0xf40 fs/attr.c:499 chown_common+0x4a0/0x660 fs/open.c:736 do_fchownat+0x147/0x240 fs/open.c:767 __do_sys_chown fs/open.c:787 [inline] __se_sys_chown fs/open.c:785 [inline] __x64_sys_chown+0x7e/0x90 fs/open.c:785 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: &ei->i_data_sem/2 --> &dquot->dq_lock --> &s->s_dquot.dqio_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&s->s_dquot.dqio_sem); lock(&dquot->dq_lock); lock(&s->s_dquot.dqio_sem); lock(&ei->i_data_sem/2); *** DEADLOCK *** 5 locks held by syz.6.4878/26133: #0: ffff888023e34460 (sb_writers#4){++++}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402 #1: ffff888074224030 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff888074224030 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: chown_common+0x33a/0x660 fs/open.c:726 #2: ffff888074223cf8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_setattr+0x92a/0x19f0 fs/ext4/inode.c:5519 #3: ffff888053d26ce8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x63/0x520 fs/quota/dquot.c:460 #4: ffff888023e34208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x12b/0x190 fs/quota/quota_v2.c:357 stack backtrace: CPU: 0 PID: 26133 Comm: syz.6.4878 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2d07/0x7d10 kernel/locking/lockdep.c:5049 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662 down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x323/0x1b70 fs/ext4/inode.c:604 ext4_getblk+0x1cc/0x6f0 fs/ext4/inode.c:890 ext4_bread+0x26/0x170 fs/ext4/inode.c:946 ext4_quota_write+0x236/0x580 fs/ext4/super.c:7222 write_blk fs/quota/quota_tree.c:70 [inline] get_free_dqblk+0x312/0x660 fs/quota/quota_tree.c:136 do_insert_tree+0x22b/0x1040 fs/quota/quota_tree.c:347 do_insert_tree+0x9eb/0x1040 fs/quota/quota_tree.c:402 dq_insert_tree fs/quota/quota_tree.c:432 [inline] qtree_write_dquot+0x49d/0x5d0 fs/quota/quota_tree.c:451 v2_write_dquot+0x108/0x190 fs/quota/quota_v2.c:361 dquot_acquire+0x2d5/0x520 fs/quota/dquot.c:472 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6831 dqget+0x778/0xeb0 fs/quota/dquot.c:988 dquot_transfer+0x37c/0x7e0 fs/quota/dquot.c:2150 ext4_setattr+0x93d/0x19f0 fs/ext4/inode.c:5520 notify_change+0xc74/0xf40 fs/attr.c:499 chown_common+0x4a0/0x660 fs/open.c:736 do_fchownat+0x147/0x240 fs/open.c:767 __do_sys_chown fs/open.c:787 [inline] __se_sys_chown fs/open.c:785 [inline] __x64_sys_chown+0x7e/0x90 fs/open.c:785 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f808259c629 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8083543028 EFLAGS: 00000246 ORIG_RAX: 000000000000005c RAX: ffffffffffffffda RBX: 00007f8082815fa0 RCX: 00007f808259c629 RDX: 000000000000000a RSI: 000000003a736e6f RDI: 0000200000000080 RBP: 00007f8082632b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8082816038 R14: 00007f8082815fa0 R15: 00007fffdb0016b8